Air compressor

ABSTRACT

An air compressor comprises a compressing device driven by a motor, a heat exchanger cooling the first air compressed by the compressing device by the second air blowing from a blower, an intake path through which the first air sucked by the compressing device flows, a discharge path through which the second air blown by the blower and heated by the heat exchanger flows, and a dehumidifying rotor that carries an adsorbent adsorbing moisture from the first air, the moisture being removed by the second air to restore the adsorbent.

BACKGROUND OF THE INVENTION

The present invention relates to an air compressor for supplying compressed dry air and particularly to an air compressor sucking dry air and discharging low-dew-point compressed air.

JP2007-7540A discloses an air compressor in which air compressed by the compressor is cooled by a freezing cycle to allow vapor in the compressed air to be condensed for dehumidifying.

JP2006-6989A discloses a hollow membrane air drier in which a polymer hollow membrane through which vapor is likely to permeate is disposed in a casing, and compressed air is supplied from a compressor to the hollow membrane so that only vapor permeates the hollow membrane to allow dehumidified compressed air to be discharged.

Recently in air compressors it was required to reduce pressure supplied to compressed air used in factories to save energy. According to reduction in supplied pressure, air per unit pressure in the air compressors is increased.

However, in the cooling air drier in JP2007-7540A, the increase in supplied air decreases dew-point performance or condensation, and in order to maintain condensation, the number of coolers is increased thereby consuming more electricity, so that energy saving could not be achieved. Pressure of compressed air is lost in a dehumidifying step, power energy of the compressor is uselessly consumed, and it is necessary to provide a processor for condensate additionally.

In order to avoid the loss in power energy and condensate processor, as described in JP2006-6989A, it is preferable to employ the hollow membrane drier having light weight and long life, but not producing condensed water. But in order to dehumidify compressed gas continuously, it is necessary to provide electricity for vacuum source for keeping the outside of the hollow membrane in low vapor partial pressure.

SUMMARY OF THE INVENTION

In view of the disadvantages, it is an object of the present invention to provide an air compressor in which its structure is simple and air is dehumidified by a dehumidifying rotor before compression to reduce consumed power for dehumidification, avoiding necessity for a condensate processor and supplying compressed air continuously.

According to the present invention there is provided an air compressor comprising:

-   -   a motor;     -   a compressing device driven by the motor;     -   a blower blowing first air;     -   a heat exchanger cooling the first air transferred from the         compressing device by second air blowing by the blower;     -   an intake path through which the first air sucked by the         compressing device flows;     -   a discharge path positioned adjacent to the intake path, the         second air heated by the heat exchanger flowing through the         discharge path; and     -   a dehumidifying rotor rotationally disposed across the intake         path and the discharge path and carrying an adsorbent adsorbing         moisture from the first air sucked by the compressing device,         moisture being removed from the adsorbent by the second air.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with respect to a preferred embodiment as shown in the accompanying drawings wherein:

FIG. 1 is a view showing air flow in an air compressor according to the present invention.

FIG. 2 is a perspective view of the air compressor.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

In FIGS. 1 and 2, an air compressor comprises a compressing device 1 in which first air is compressed; a motor 2 for driving the compressing device 1; a heat exchanger 3 for cooling the first air compressed by and transferred from the compressing device 1; a blower 4 for blowing second air as cooling wind to the heat exchanger 4; and a cylindrical dehumidifying rotor 5 for adsorbing moisture from the first air sucked into the compressing device 1.

The compressing device 1 sucks the first air which is dehumidified with the dehumidifying rotor 5 from an sucking tube 6, and the first air compressed by the compressing device is transferred to the heat exchanger 3 via a first conduit 7.

The heat exchanger 3 cools the first air conveyed from the first conduit 7, by the second air as cooling wind which is blown from the blower 4, conveys the first air to a second conduit 8 and supplies the second air heated by the heat exchanger 3, to the dehumidifying rotor 5.

The dehumidifying rotor 5 is disposed across an intake path 9 through which the first air sucked by the compressing device 1 flows, and a discharge path 11 through which the second air blown from the blower 4 and heated by the heat exchanger 3 flows. The dehumidifying rotor 5 is rotated by a motor 12.

For example, the dehumidifying rotor 5 may be rotated by the motor 12 via a belt 13 wound on the outer circumference of the dehumidifying rotor 5, or via a gear or an elastic roller such as rubber between the dehumidifying rotor 5 and a rotary shaft of the motor 12.

The dehumidifying rotor 5 carries an adsorbent containing silica gel or zeolite as main component adsorbing moisture in the air. The moisture in the absorbent of in the dehumidifying rotor 5 is removed by the second air heated by the heat exchanger 3. The dehumidifying rotor 5 rotates circumferentially to allow the adsorbent to move from an adsorbing area 14 for adsorbing moisture to a restoration area 15 where moisture is removed.

The dehumidifying rotor 5 comprises the adsorbing area 14 through which the intake path 9 passes and the restoration area 15 through which the discharge path 11 passes. The first air which flows in from the air inlet 16 is supplied in the adsorbing area 14 to dehumidify the first air. The second air passes through the restoration area 15 and is sent to an air outlet 17 thereby restoring the adsorbent so that the adsorbent can adsorb moisture more effectively.

Silica gel or zeolite may be used as adsorbent in the dehumidifying rotor 5. Silica gel and zeolite have different moisture absorbency depending on each porosity. For example, in zeorite, moisture absorbency rises sharply at relative humidity in which vapor pressure of water is low. When relative humidity becomes more than 10%, increase ratio in moisture absorbency becomes small significantly. Meanwhile, in silica gel, moisture absorbency increase gently with increase in relative humidity, and moisture absorbency significantly increases in high relative humidity area.

In the embodiment, when the air compressor is disposed in a high-relative-humidityconditions, silica gel is carried in the dehumidifying rotor 5. In the meantime, when the air compressor is disposed in a low-relative-humidity or relatively high temperature conditions, zeolite may preferably be carried in the dehumidifying rotor 5.

In this embodiment, the air compressor provides a dehumidifying cycle for air, comprising the dehumidifying step for taking the first air in through the air inlet 16 by sucking air by the compressing device 1 and dehumidifying the first air by the dehumidifying rotor 5; the compression step for sucking the first air into the compressing device 1 via the sucking tube 6; the cooling step for allowing the first air compressed by the compressing device 1 to pass through the first conduit 7 to cool the first air by the heat exchanger 3; and the discharging step for discharging the first air, from the heat exchanger 2 to the second conduit 8.

The air compressor provides a restoring cycle comprising the cooling step for blowing the second air blown by the blower 4 from the outside to the heat exchanger 3; the restoring step for restoring the adsorbent in the restoration area 15 of the dehumidifying rotor 5 by the second air heated by the heat exchanger 3; and the discharge step for discharging the second air from the restoration area 15 to the air outlet 17.

As mentioned above, in addition to the embodiments, the cylindrical dehumidifying rotor in this invention may preferably be a honeycomb rotor that carries high dehumidifying zeolite or silica gel a rotor-like honeycomb structure wound or layered by manufacturing inflammable inorganic fibers such as ceramic fibers into cardboards.

The foregoing merely relates to an embodiment of the invention. Various variations may be made by person skilled in the art without departing from the scope of claims wherein: 

1. An air compressor comprising: a motor; a compressing device driven by the motor to suck and compress first air; a blower blowing second air; a heat exchanger cooling the first air transferred from the compressing device by second air blowing by the blower; an intake path through which the first air sucked by the compressing device flows; a discharge path positioned adjacent to the intake path, the second air heated by the heat exchanger flowing through the discharge path; and a dehumidifying rotor disposed across the intake path and the discharge path and carrying an adsorbent adsorbing moisture from the first air sucked by the compressing device, the moisture being removed from the adsorbent by the second air.
 2. The air compressor of claim 1 wherein the dehumidifying rotor comprises an adsorbing area and a restoration area partitioned from each other, the adsorbing area adsorbing moisture into the adsorbent from the first air sucked by the compressing device, the adsorbent being restored in the restoration area by the second air heated by the heat exchanger.
 3. The air compressor of claim 1 wherein the adsorbent comprises silica gel.
 4. The air compressor of claim 1 wherein the adsorbent comprises zeolite.
 5. The air compressor of claim 1 wherein the dehumidifying rotor is rotated with a belt wound an outer circumference and driven by a motor via the belt. 